This invention relates to a trailerable earth digging apparatus and particularly to a trailerable backhoe unit adapted to be releasably interconnected to an automobile, pickup truck, or other small over-the-road vehicle for transportation between digging sites.
In building, landscaping and various construction applications, earth moving equipment is required for digging an appropriate hole, trench or the like in the ground.
A backhoe unit is widely used for trenching and other forms of earth digging. In many instances, a rather limited amount of digging is required and conventional large digging apparatus is not essential or desirable.
Earth moving equipment is transported from one site to the next. Earth moving equipment is generally provided with power driven means for moving about the digging site, but the construction is not adapted to over-the-road movement. Although digging equipment such as a backhoe may be available in different sizes, commercially available equipment is generally of a large, heavy construction to permit both large and small excavation and is adapted for transport only on a separate trailer and vehicle.
A backhoe unit, to which the present invention is particularly directed, generally includes a boom-mounted bucket assembly having a pivot support connected to the machine frame structure and a series of interconnected pivot arms interconnectd between the pivot support and a bucket for articulated movement of the bucket. This permits the dropping of the bucket into the earth and then drawing of the bucket towards the main frame for purposes of removing the earth from the ground area.
In the digging operation, the backhoe apparatus must be firmly stabilized to permit creation of the digging forces required for the removal of the earth. In one conventional system, the back-hoe apparatus is interconnected to the back end of an earth moving tractor having a large bucket at the forward end. Alternatively, special back-hoe apparatus is constructed having a supporting wheeled structure and the articulated boom assembly connected to the frame structure. A separate engine-driven hydraulic supply system provides hydraulic power to the several hydraulic motor means connected to the boom assembly and to the machine.
The prior patent art does include suggestion of relatively small digging apparatus of the back-hoe variety and a unit which can be attached to a garden tractor or the like is shown in U.S. Pat. No. 3,362,548 which issued Jan. 9, 1968 to K. G. Cunningham. The back-hoe bucket assembly shown in particularly shown releasably interconnected to the forward end of a two-wheel garden tractor. A coupling unit interconnects a hydraulic operating system to the internal combustion engine of the two-wheel garden tractor. Although this provides a small portable system, the assembly requires separate over-the-road transport apparatus, such as a vehicle and trailer, to conveniently transport the combination between widely spaced digging sites.
U.S. Pat. No. 3,635,364 discloses a further digging apparatus of the back-hoe variety. The apparatus includes a wheeled assembly having a forwardly extended towing mechanism. The wheel structure is pivotally mounted to a frame for raising of the wheel during a digging operation. A towing mechanism extends forwardly beneath the boom, with the boom assembly located between the towing vehicle and the wheel support. This of course creates a significant load on the vehicle during the towing operation, and would normally require a rather large powered vehicle and does not provide convenient on-site movement.
Other patents disclose other back-hoe digging apparatus. For example, see U.S. Patents in which various constructions are shown.
Although, various smaller modifications have thus been suggested, they are not adapted to provide a truly trailerable back-hoe apparatus which can be conveniently interconnected to an automobile or other similar vehicles for transport from site to site. Further, the smaller units do not generally permit significant on-site travel means or significant digging capability.
For example, the inventor does not know of any small back-hoe apparatus which is adapted to digging of a trench to the depth of six to eight feet. Further, none of the devices will permit the convenient trenching or other digging on a significantly inclined terrain.
There is therefore a very significant need for a small, trailerable back-hoe digging apparatus which can be conveniently transported from site-to-site without the necessity of loading on a trailer or the like.